Thank you all. The hardest part about losing Ian was that until he came up with that expletive-deleted lump, he showed no signs of aging except for silvering of his eyebrows and beard. Still fit and active, still bouncing around like a youngster.
My retired and rejected racing Greyhounds routinely live to 15 without complications. Two of my remaining dogs, a Greyhound and a GSD mix, are both 12 and still tear around like lunatics (the third one, a just-coming-3yo Greyhound, IS a lunatic). Losing a dog at only 10+ seems far too soon.